These diseases are generally due to the presence, on the inner walls of the canal, of deposits which cause constriction or stenosis therein.
A catheter is generally used for treating such diseases:
on the one hand, to restore the normal flowing section of the canal in the stenosis area by compression applied by a balloon, PA1 on the other hand, to inject, for example through the balloon wall, a treating product intended to make the restored flowing section of the canal last, if necessary by forming in situ a prosthesis of corresponding section. PA1 an outer tubular element comprising a distal part and a proximal part, provided at the level of its distal part with a radially deformable portion comprising a balloon, and on either side of said balloon with at least one orifice communicating with said body canal and allowing the fluid flowing in the body canal to flow through said outer tubular element; PA1 an inner tubular element, situated inside said outer tubular element, and allowing the passage of a guide; PA1 a micro-tube, placed preferably inside said outer tubular member, issuing at one end inside said balloon and connected at its other end to a fluid supply source in order to enable the inflating and deflating of said balloon, characterized in that: PA1 said balloon has an outer wall designed to come into contact with the inner wall of said body canal, while in position of use; and an inner wall fixed in tight manner to said outer wall and adapted to define therewith, while in the position of use, an inner annular cavity; PA1 end in that it further comprises a support element shaped so as to hold said inner wall of the balloon, in position of use, while allowing the body fluid to flow in the space between said inner element and the inner wall of the balloon.
Normally, during the compression (crushing of the deposits with the balloon), the canal is entirely obturated by the balloon. Yet, it is necessary, during the intervention, to keep up a minimum flow of fluid in the canal, in order to prevent any risks of damage to the tissues or organs situated downstream of the balloon.
Various solutions have been proposed in the prior art in order to solve this problem.
For example, in U.S. Pat. Nos. 4,771,777, 4,790,315 or 4,892,519, it has been proposed to make the body fluid flow through the inner tabular member of the dilation catheter through which passes the guide.
This solution, however, is not satisfactory in that the body fluid flowing section is limited, on the one hand, because of the small diameter of the inner tubular member, and on the other hand, because of the presence of the guide.
In U.S. Pat. No. 5,000,734, it is proposed to make the body fluid flow through the balloon. To this effect, the balloon comprises, when in the inflated state, a plurality of longitudinal conduits.
This solution which constitutes an improvement over that described in the aforecited documents, is not altogether satisfactory.
Indeed, as it appears, the body fluid flowing section is dependent on the number and diameter of the conduits provided on the balloon.
Yet, such conduits are relatively difficult to produce and too high a number of them would badly affect the mechanical resistance of the balloon.